[llvm-dev] [RFC] Removing debug locations from ConstantSDNodes

[Anton Korobeynikov via llvm-dev]

Sorry to resurrect the old thread – I completely missed it!

On Thu, Jun 21, 2018 at 6:08 AM via llvm-dev <llvm-dev at lists.llvm.org> wrote:

> +1.  Constants are not inherently interesting, but loading one as an action preparatory to computing a value or setting up a parameter in a call, the instruction ought to be associated with the relevant source statement.
And now we have a clear problem. I'm seeing many cases when such
instruction got associated with the *previous* source statement which
does not make any sense at all. This happens because the constant now
is location-less and therefore the location of such
constant-materialization instruction is implicitly defined by the
previous available location.

This seems to be quite a serious regression in the quality of the
debug info produced by selection dag isel in LLVM 7 release as
compared to LLVM 6.

--
With best regards, Anton Korobeynikov
Department of Statistical Modelling, Saint Petersburg State University